| Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter units -> Monitor Keywords |
|
|
  Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter unitsUSPTO Application #: 20070253831Title: Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter units Abstract: A system for maintaining at least one air characteristic in an air ventilated facility using at least one fan filter unit, the system comprising at least one sensor for sensing the at least one air characteristic, the at least one sensor being exposed to the air ventilated facility; the at least one sensor being operatively connected to a control system that is operatively connected to the at least one fan filter unit; the control system receiving output readings from the at least one sensor and determining if the output reading is within a range and, in response to a negative determination, providing a command to the at least one fan filter unit to adjust the at least one fan filter unit operating speed. A corresponding method and apparatus are also disclosed. (end of abstract)
Agent: Law Offices Jacobson Holman - Washington, DC, US Inventor: Zong Tang Lee USPTO Applicaton #: 20070253831 - Class: 417 5 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20070253831. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001]This invention relates to a method and apparatus for maintaining room characteristics in an air ventilated facility by using a fan filter unit. BACKGROUND OF THE INVENTION [0002]It is common for modern production and testing facilities to control particles in the air that circulates within an air ventilated facility in order to ensure the quality of output. An example of such a facility is a clean room. Whether be it wafer dies, compact discs, memory disk drives or food, particle content in the air that circulates within the air ventilated facility needs to be maintained at or below acceptable levels. Also, air needs to be circulated for workers to be able to breathe. [0003]Also, at least one fan filter unit is used to overpressure the air in the air ventilated faciliting to reduce the likelihood of particles entering from outside the air ventilated facility. The air pressure in the air ventilated facility is normally higher than that in the ceiling interspace, and other exterior areas, to reduce the likelihood of dirty air from leaking into the facility. The higher the pressure difference, the lower the possibility of air leakage into the facility. [0004]However, the ability of the fan filter unit to provide overpressure in the facility depends on the amount of air the fan filter units are able to draw from, for example, the ceiling interspace or ducts that connect the fan filter units. Some of the factors affecting this include: [0005]actual site condition such as, for example, building beam obstruction; [0006]weak air supply for a fan filter unit farthest from an air supply; and [0007]fluctuation in the rate and volume of the air supply. [0008]The inability or failure of a fan filter unit to draw sufficient air will result in a reduction of positive air pressure in at least a part of the facility, and may compromise the cleanliness of the facility. [0009]One way of determining the effect of air pressure fluctuations is by measuring the airflow volume or airflow speed directly below a fan filter unit. Airflow speed.times.filter surface area=airflow volume. The greater the pressure loss from a fan filter unit due to any one or more of the reasons given above will mean a slower air speed below the fan filter unit. [0010]The known method of ensuring adequate positive air pressure involves the physical and manual process of measuring the pressure in the facility at several different locations, one location at a time, using portable measuring devices. Subsequently there is the time consuming process of using trial and error to adjust the fan speed of the various fan filter units to meet the required pressure. This is often by-passed by operating all fan filter units at maximum speed. This can create an excess overpressure, and is energy inefficient. [0011]Also, there is often a requirement for one location in the facility to be at an air pressure higher than the surrounding space. This may require a high air flow for that location. [0012]Further, there may be a popular requirement for the whole confined space to have a very even airflow at a specific location of the area due to the requirements of, for example, a delicate manufacturing process, because an uneven airflow may cause a lower yield rate. This is important in certain industries such as, for example, the fabrication of computer chips, TFT-LCD, and so forth. This is often by-passed by adjusting the airflow of each fan filter unit in small groups of fan filter units one group at a time. The adjustment of one group will affect the airflow (air pressure) of another group. In the many production plants, it is not uncommon to have thousands of fan filter units in a confined space such as, for example, a clean room where airflow evenness at any location is a must for reliable production. To achieve evenness in airflow it may take weeks by many rounds adjustment using trial and error. There are many other situations which may affect airflow evenness such as, for example, but not limited to, a failure of one or more fan filter units. SUMMARY OF THE INVENTION [0013]In accordance with a first preferred aspect there is provided a system for maintaining at least one air characteristic in an air ventilated facility using at least one fan filter unit, the system comprising: [0014](a) at least one sensor for sensing the at least one air characteristic, the at least one sensor being exposed to the air ventilated facility; [0015](b) the at least one sensor being operatively connected to a control system that is operatively connected to the at least one fan filter unit; [0016](c) the control system receiving output readings from the at least one sensor and determining if the output reading is within a range and, in response to a negative determination, providing a command to the at least one fan filter unit to adjust the at least one fan filter unit operating speed. [0017]According to a second preferred aspect there is provided a method for maintaining at least one air characteristic in an air ventilated facility using at least one fan filter unit, the method comprising: [0018](a) using at least one sensor to sense the at least one air characteristic, the at least one sensor being exposed to the air ventilated facility; [0019](b) the at least one sensor being operatively connected to a control system that is operatively connected to the at least one fan filter unit; [0020](c) obtaining output readings of an air characteristic from the at least one sensor at the control system; [0021](d) determining if the output reading is within a range; and [0022](e) in response to a negative determination, providing a command to the at least one fan filter unit to adjust the at least one fan filter unit operating speed. [0023]According to a third preferred aspect there is provided apparatus for maintaining at least one air characteristic in an air ventilated facility using at least one fan filter unit, the apparatus comprising: [0024](a) at least one sensor for sensing the at least one air characteristic, the at least one sensor being exposable to the air ventilated facility; [0025](b) the at least one sensor being for operative connection to a control system that is operatively connectable to the at least one fan filter unit; [0026](c) the control system being for receiving output readings from the at least one sensor and determining if the output reading is within a range and, in response to a negative determination, providing a command to the at least one fan filter unit to adjust the at least one fan filter unit operating speed. [0027]For all three aspects, the at least one sensor may be for sensing at least one of: air flow rate, air pressure, air temperature, air particle count sensor, and air humidity. The at least one sensor may be locatable in, on, above or underneath a ceiling panel of the air ventilated facility and/or a fan filter unit, on top of the at least one fan filter unit, attached to an exterior casing of the at least one fan filter unit, above the ceiling panel; and may be able to be operatively connected to the control system by one of: wirelessly, by a control cable in common with the at least one fan filter unit, and by a control cable independent of the at least one fan filter unit. There may also be provided an audible alarm able to be operatively connected to the control system. The control system may comprise a plurality of sub-controllers. There may be a plurality of sensors that able to operate independently of each other, and a plurality of fan filter units each being able to be independently commanded by the control system. [0028]For all three aspects there may be a plurality of fan filter units arranged in a plurality of groups. Alternatively, the sensors may operate independently of each other. There may be a plurality of sensors, each sensor being operatively associated with a fan filter unit and/or a group of fan filter units. [0029]The obtaining of the output readings may be by one or more of: polling, reading and receiving. [0030]The adjustment in (e) may be to increase the at least one fan filter unit operating speed if the output reading is below the range, and to decrease the at least one fan filter unit operating speed if the output is above the range. Alternatively, the adjustment in (e) may be to decrease the at least one fan filter unit operating speed if the output is below the range, and to increase the at least one fan filter unit operating speed if the output is above the range. The adjustment may be by a preset factor. A direction of the adjustment may be determined by the air characteristic. The method may further comprise determining if the sensing is to be for all of the at least one fan filter units, or is a local sensing for all the at least one fan filter units servicing a local area or location. In response to a positive determination, there may be included waiting a predetermined time before repeating the method. After the adjustment there may be included waiting before repeating the method. BRIEF DESCRIPTION OF THE DRAWINGS [0031]In order that the present invention may be fully understood and readily put into practical effect, there shall now be described by way of non-limitative example only preferred embodiments of the present invention, the description being with reference to the accompanying illustrative drawings. In the drawings: [0032]FIG. 1 is a schematic drawings side view of a prior art system; [0033]FIG. 2 is a schematic view of a preferred embodiment; Continue reading... Full patent description for Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter units Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter units patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter units or other areas of interest. ### Previous Patent Application: Transportation unit for a wind turbine rotor blade Next Patent Application: Pump set with safety interlock Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Method and apparatus for maintaining air characteristics in an air ventilated facility using fan filter units patent info. IP-related news and info Results in 5.7586 seconds Other interesting Feshpatents.com categories: Novartis , Pfizer , Philips , Polaroid , Procter & Gamble , |
||
